diff --git a/src/core/main.c b/src/core/main.c
index 7fc06bea0..954b480fd 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -1650,6 +1650,7 @@ int main(int argc, char *argv[]) {
         /* This will close all file descriptors that were opened, but
          * not claimed by any unit. */
         fdset_free(fds);
+        fds = NULL;
 
         if (serialization) {
                 fclose(serialization);